1. Field of the Invention
The present invention generally relates to a timing control circuit, an image display apparatus, and an evaluation method of the image display apparatus, and especially relates to a timing control circuit, an image display apparatus and an evaluation method of the image display apparatus, evaluation of which is performed by displaying a predetermined image on a display panel.
2. Description of the Related Art
Conventionally, an EMI (Electromagnetic Interference) evaluation of an image display apparatus, such as an LCD (Liquid Crystal Display), has been performed by a system as shown in FIG. 1.
FIG. 1 shows a block diagram of an example of a system that performs EMI evaluation of an LCD. As for the system of FIG. 1, an LCD 1 and a personal computer (henceforth PC) 2 are connected through a cable 3.
Here, the PC 2 transmits a signal (for example, a clock signal, a display enable signal, and a display-data signal) to a timing controller 10 of the LCD 1 through the cable 3 such that the LCD 1 displays a predetermined image for EMI evaluation.
The timing controller 10 generates a gate driver control signal (for example, a gate clock signal, and a gate start signal) that controls a gate driver 11, using the signal received from the PC 2, and transmits the gate driver control signal to the gate driver 11. Further, the timing controller 10 generates a source driver control signal (for example, a dot clock signal, an output-control signal, a polarity signal, a display data signal, a data start signal) that controls a source driver 12, using the signal received from the PC 2, and transmits the source driver control signal to the source driver 12.
The gate driver 11 and the source driver 12 display the predetermined image for EMI evaluation on a liquid crystal panel 13 according to the gate driver control signal and the source driver control signal, respectively. Here, in the liquid crystal panel 13, pixels are provided in a matrix form, each pixel including a TFT (Thin Film Transistor) 17 that is connected to a liquid crystal capacitor 18, a data (source) bus line 15, and a gate bus line 16.
That is, the LCD 1 receives a signal required in order to display the predetermined image for EMI evaluation from the PC 2, and displays the predetermined image for EMI evaluation on the liquid crystal panel 13 according to the received signal.
As described above, the EMI evaluation of the LCD 1 is performed while the predetermined image for EMI evaluation is displayed on the liquid crystal panel 13. That is, the LCD 1 has to keep receiving a signal required in order to display the predetermined image for EMI evaluation from the PC 2 during the EMI evaluation.
Therefore, in the system of FIG. 1, a problem is that the PC 2 and the cable 3 are indispensable in addition to the LCD 1, which makes it difficult to identify which of the LCD 1, the PC 2, and the cable 3 is generating and radiating an EMI. Consequently, in the system of FIG. 1, it is difficult to measure an EMI of the LCD 1 itself.
The present invention is made in view of the above-mentioned point, and aims at offering a timing control circuit, an image display apparatus, and an evaluation method of the image display apparatus that realize evaluation of the image display apparatus by displaying a predetermined image on a display panel, eliminating influences of the PC 2 and the cable 3.